A number of isoindole-type compounds are known in the prior art. Recently, in German Offenlegungsschrift No. 2,165,651, a group of isoindol-1,3-diones which are useful as herbicides was disclosed. The general formula for the isoindol-1,3-diones is as follows: ##SPC2##
Wherein R may be an aryl, aralkyl or benzyl optionally substituted with 1 to 5 halogen atoms; hydroxy, nitro, cyano, thiocyano, carboxy, halogenated alkyl, or alkyl, or alkoxy, lower alkylthio, phenyl groupings and a group having the configuration --O--CH.sub.2 A may also be substituted therein, wherein A is a phenyl or a naphthyl group, wherein the phenyl group may have one or more substitutions therein, such as halogen atoms, nitro groupings, lower alkyl groupings or lower alkoxy groupings.
Typical of the compounds disclosed in the Offenlegungsschrift is the compound of Example 1: ##SPC3##
Although herbicides such as the herbicide discussed above have proven effective in controlling undesired vegetation there is a constant need for improved herbicides because of the current critical food shortages in the world. Any improvement in herbicidal activity, in conjunction with no significant damage to the crop which is to be protected, is desirable. Consequently, it is readily apparent that there is a continuing need for improved herbicides.
According to the instant invention, novel, improved herbicides have been discovered.